Ophthalmic compositions comprising povidone-iodine

ABSTRACT

A topical ophthalmic composition comprised of povidone-iodine 0.01% to 10.0% combined with a steroid or non-steroidal anti-inflammatory drug. This solution is useful in the treatment of active infections of at least one tissue of the eye (e.g., conjunctiva and cornea) from bacterial, mycobacterial, viral, fungal, or amoebic causes, as well as treatment to prevent such infections in appropriate clinical settings (e.g. corneal abrasion, postoperative prophylaxis, post-LASIK/LASEK prophylaxis). Additionally the solution is effective in the prevention of infection and inflammation in the post-operative ophthalmic patient.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/789,130, filed Mar. 7, 2013, which issued as U.S. Pat. No. 8,765,724and which is a continuation of U.S. application Ser. No. 12/845,544,filed Jul. 28, 2010, which issued as U.S. Pat. No. 8,394,364 and whichis a divisional of U.S. application Ser. No. 11/636,293, filed Dec. 7,2006, which issued as U.S. Pat. No. 7,767,217 and claims the benefit ofpriority from U.S. Provisional Application Ser. No. 60/782,629 filedMar. 14, 2006 and U.S. Provisional Application Ser. No. 60/848,315 filedSep. 29, 2006, all of which are hereby incorporated by reference intheir entireties. All patents, patent applications, and references citedanywhere in this specification are hereby incorporated by reference intheir entirety.

BACKGROUND OF THE INVENTION

Infectious conjunctivitis is an ophthalmic disorder characterized byinflammation of the conjunctiva secondary to invasion of a microbe.Microbes capable of causing conjunctivitis in humans include bacteria(including Mycobacteria sp), viruses, fungi, or amoebae. Currenttreatment for bacterial conjunctivitis consists of antibiotic drops.Because antibiotic drops are ineffective against viral conjunctivitis,treatment of such infections consists only of relieving symptoms.Treatments for fungi and amoeba conjunctivitis consist of a smallselection of medications which lacks anti-bacterial or anti-viralactivity and which, in addition, is toxic to the ocular surface.

Diagnosis of the various causative agents such as bacteria, virus, orfungus, in infectious conjunctivitis is not economically feasiblebecause accurate diagnosis requires sophisticated laboratory culture noteasily integrated into the average healthcare practice. Because accuratediagnosis is impractical, most conjunctivitis is presumed to bebacterial without culturing and is treated with antibiotics. Antibiotictreatment is suboptimal because it is ineffective against viral orfungal conjunctivitis.

The use of steroids is approached cautiously in the setting of ocularinfection. While steroids can have the benefit of reducing the severityof the inflammation in an acute infection, they are also known toincrease susceptibility to certain infections.

Topical corticosteroids are routinely used to control ocularinflammation. Their mechanism of action involves the inhibition of theimmune response and the subsequent tissue destruction that exuberantinflammation may cause. Corticosteroid has the undesirable side effectof limiting the body's intrinsic ability to fight infection. In fact,inopportune steroids usage can worsen the course of an infectionsecondary to mycobacteria, virus, or fungus. Thus, the use of a combinedantimicrobial-steroid medication in ocular infections is recommendedonly under careful observation of a trained ophthalmologist because ofthese significant risks. In fact, Tobradex® (Alcon), the most commonlyprescribed combination ophthalmic antimicrobial-steroid drug,specifically lists ‘viral disease of the cornea and conjunctiva,mycobacteria infection, and fungal infection’ as absolutecontraindications to its use. Clearly, these combination drugs were notintended to be used in the face of infectious conjunctivitis in whichbacterial infection cannot be confirmed.

In summary, there is currently no ophthalmic antimicrobial drug withbroad activity against all the causes of conjunctivitis or keratitis,and there is currently no approved antimicrobial/steroid, orantimicrobial/non steroidal anti-inflammatory combination drug that canbe safely used in infectious conjunctivitis or keratitis that canpotentially be viral or fungal in origin.

SUMMARY OF THE INVENTION

The invention is an ophthalmic composition comprised of povidone-iodine0.01%-10% (weight/weight or weight/volume) combined with ananti-inflammatory medication, a steroid, or a combination of bothanti-inflammatory and a steroid. In a preferred embodiment, thepovidone-iodine (PVP-I) is between 0.1% and 2.5%, between 0.5 and 2%,between 0.75 and 2%, between 0.8 and 2%, between 0.9 and 2%, between 1%and 2% or between 1% and 1.5%. In another embodiment, the total weightof the PVP-I, anti-inflammatory and steroid is between 0.1% and 4.5%.This solution is useful in the treatment of infections of theconjunctiva and cornea. The broad spectrum of povidone-iodine wouldallow this combination to be used in cases of ocular conjunctival orcorneal infection caused by mycobacteria, viruses, fungi, and amoeba;this is in distinction to currently available combinationantimicrobial-steroid ophthalmic compositions, which are contraindicatedin the aforementioned infections. Additionally the solution will beuseful in the infectious prophylaxis and inflammatory control ofpatients recovering from recent ophthalmic surgery. There are nocurrently available antimicrobial/anti-inflammatory orantimicrobial/steroid combinations useful for viral, fungal,mycobacterial and amoebic infections in the post-operative period.

One embodiment of the invention is directed to an ophthalmic compositionsuitable for topical administration to an eye, effective for treatmentand/or prophylaxis of a microorganism infection or a disorder of atleast one tissue of the eye. Prophylaxis may be, for example,prophylaxis from infection following surgery, prophylaxis from infectionafter birth for the newborn, or prophylaxis from accidental contact withcontaminating material. Accidental contact with contaminating materialmay occur, for example, during surgery or during food processing. Thecomposition comprises povidone-iodine in a concentration between 0.01%to 10%, and an anti-inflammatory, a steroid, or a combination thereof.

The mammalian eye can be divided into two main segments: the anteriorsegment and the posterior segment. The anterior segment is the frontthird of the eye that includes the tissues in front of the vitreoushumor: the cornea, iris, ciliary body, and lens. Within the anteriorsegment are two fluid-filled spaces: the anterior chamber and theposterior chamber. The anterior chamber is located between the posteriorsurface of the cornea (i.e. the corneal endothelium) and the iris. Theposterior chamber is located between the iris and the front face of thevitreous. The posterior segment is the back two-thirds of the eye thatincludes the anterior hyaloid membrane and all tissues behind it: thevitreous humor, retina, choroid, and optic nerve. In some animals, theretina contains a reflective layer (the tapetum lucidum) which increasesthe amount of light each photosensitive cell perceives, allowing theanimal to see better under low light conditions.

It was surprising to discover that the formulations of povidone-iodinecombined with steroids, when present in a suitable pH range, eliminatedthe undesired irritating effect of PVP-I to the eye. The inventionprovides pH stable aqueous suspensions of water-insoluble drugs thatremain in such a state even after extended periods of storage.

In a preferred embodiment, the ophthalmic composition containspovidone-iodine at a concentration between 0.1% and 2.5% by weight, ormore preferably, between 0.5% and 2% by weight. In another preferredembodiment, the ophthalmic composition has a total weight ofpovidone-iodine, an anti-inflammatory, a steroid of between 0.1% to 2.5%(weight to volume, or weight to weight) or between 0.1% to 4.5%.

The steroid of the ophthalmic composition may be at a concentration ofbetween 0.01 and 10%. In a preferred embodiment, the steroid is at aconcentration of between 0.05 and 2%.

The ophthalmic composition may further comprise (1) a topical anestheticwhich relieves pain (2) a penetration enhancer which enhances thepenetration of povidone-iodine into the tissues of the eye (this may bea topical anesthetic) (3) an antimicrobial preservative, which, forexample, may be at a concentration of about 0.001% to 1.0% by weight;(4) a co-solvent or a nonionic surface agent—surfactant, which, forexample, may be about 0.01% to 2% by weight; (5) viscosity increasingagent, which, for example, may be about 0.01% to 2% by weight; and (6) asuitable ophthalmic vehicle.

The ophthalmic composition may be in the form of a solution, asuspension, an emulsion, an ointment, a cream, a gel, or acontrolled-release/sustain-release vehicle. For example, the compositionmay be in the form of a contact lens solution, eyewash, eyedrop, and thelike.

The ophthalmic composition may be used for treatment and/or prophylaxisof a microorganism infection. The microorganism may be a bacterium, avirus, a fungus, or an amoeba, a parasite, or a combination thereof. Thebacteria may be a mycobacterium. Further, the solution may be used totreat or for prophylaxis of disorders such as conjunctivitis, cornealabrasion, ulcerative infectious keratitis, epithelial keratitis, stromalkeratitis and herpesvirus-related keratitis.

For example, the ophthalmic composition may comprise the following: 0.5to 2% (w/w) polyvinylpyrrolidinone-iodine complex; 0.05 to 2% (w/w)steroid; 0.005% to 0.02% (w/w) EDTA (ethylenediaminetetraacetic acid);0.01 to 0.5% (w/w) sodium chloride; 0.02 to 0.1% (w/w) tyloxapol; 0.5%to 2% (w/w) sodium sulfate; and 0.1 to 0.5% (w/w) hydroxyethylcellulose;at pH range from 5 to 7. More specifically, the ophthalmic compositionmay comprise the following: 1.0% (w/w) polyvinylpyrrolidinone-iodinecomplex; 0.1% (w/w) steroid; 0.01% (w/w) EDTA dehydrate; 0.3% (w/w)sodium chloride salt; 0.05% (w/w) tyloxapol; 1.2% (w/w) sodium sulfate;and 0.25% (w/w) hydroxyethylcellulose; at pH range from 5.5 to 6.5. Inone embodiment, the composition consists essentially of 0.5 to 2% (w/w)polyvinylpyrrolidinone-iodine complex; 0.05 to 2% (w/w) steroid; 0.005%to 0.02% (w/w) EDTA (ethylenediaminetetraacetic acid); 0.01 to 0.5%(w/w) sodium chloride; 0.02 to 0.1% (w/w) tyloxapol; 0.5% to 2% (w/w)sodium sulfate; and 0.1 to 0.5% (w/w) hydroxyethylcellulose; at pH rangefrom 5 to 7. In another embodiment, the composition consists essentiallyof 1.0% (w/w) polyvinylpyrrolidinone-iodine complex; 0.1% (w/w) steroid;0.01% (w/w) EDTA disodium salt; 0.3% (w/w) sodium chloride salt; 0.05%(w/w) tyloxapol; 1.2% (w/w) sodium sulfate; and 0.25% (w/w)hydroxyethylcellulose; at pH range from 5.5 to 6.5.

It is known, of course, that EDTA can be in many forms such as a freeacid, disodium, or tetrasodium salts. The steroid may be dexamethasone,prednisolone or prednisone. These steroids may be in their sodiumphosphate form (e.g., dexamethasone sodium phosphate, prednisolonesodium phosphate, or prednisone sodium phosphate) or acetate form (e.g.,dexamethasone acetate, prednisolone acetate, or prednisone acetate).Prednisolone is an active metabolite of prednisone and it is understoodthat prednisone may be used instead of prednisolone.

In a preferred embodiment, the ophthalmic composition retains at least90% of its PVP-I and at least 90% of its steroid after 1 month, 2months, 3 months, 6 months or 1 year after it is manufactured. This canbe accomplished, at least, by producing the ophthalmic compositionaccording to the formula listed above (e.g. previous two paragraphs).This stability is maintained even when the composition is stored at roomtemperature in a lighted indoor environment of 100 lux to 1000 lux. Inone preferred embodiment, the composition is an aqueous solution.

In another embodiment, the invention is directed to a method fortreating and/or prophylaxis of an eye disorder or a microorganisminfection of at least one tissue of the eye comprising the step ofadministering one of more doses of an ophthalmic composition, discussedabove, to the eye. The eye disorder may be, for example, a microorganisminfection of at least one tissue of the eye, conjunctivitis, cornealabrasion, ulcerative infectious keratitis, epithelial keratitis, stromalkeratitis and herpesvirus-related keratitis. The microorganism may be abacteria (e.g., mycobacteria), virus, fungi, or amoebae.

In the method, the treatment may comprise administering a solution ofthe invention where the sum of the povidone-iodine, theanti-inflammatory, and the steroid is between 0.001 mg to 5 mg per dose.Further, the dose volume may be between 10 microliters to 200microliters or between 50 microliters to 80 microliters; about one dropper eye. Administration may be between 1 to 24 times a day, between 2 to4 times a day or between 2 to 24 times a day.

In one embodiment, the method further comprises a step of storing thesolution for at least one month, at least two months, at least threemonths, at least six months, or at least one year before it isadministered. The storage may be in a clear bottle (a container thatdoes not substantially block light) in a lighted environment. A lightedenvironment may be, for example, an indoor lighted environment withabout 100 lux to 1000 lux of light.

DETAILED DESCRIPTION OF THE INVENTION

In a preferred embodiment, the compositions of the present invention areadministered topically. The dosage range is 0.001 to 5.0 mg/per eye;wherein the cited mass figures represent the sum of the threecomponents: anti-inflammatory, povidone-iodine and topical anesthetic.Dosage for one eye is understood to be about one drop of solution. Onedrop of solution may be between 10 μl to 200 μl between 20 μl and 120μl, or between about 50 μl (microliters) to about 80 μl of solution orany values in between. For example, dispensers such as pipettors candispense fluid drops from at least 1 μl to 300 μl and any value inbetween.

In a preferred embodiment, the solution may be administered as an eyedrop using any of the many types of eye drop dispensers on the market.Although not required, the container for the compositions of theinvention may be clear, translucent, and opaque and may contain otherproperties or combination of properties such as being glass lined,tamper proof, packaged in single or few dose aliquots, and a combinationthereof.

Povidone-iodine has the following chemical structure:

Suitable anti-inflammatories for the compositions and methods of theinvention include, at least, the following: ketotifen fumarate,diclofenac sodium, flurbiprofen sodium, ketorlac tromethamine, suprofen,celecoxib, naproxen, rofecoxib, or a derivative or combination thereof.

Ketorolac (also called ketorlac, or ketorolac tromethamine) is anon-steroidal anti-inflammatory drug (NSAID) in the family of propionicacids.

Suitable steroids for the compositions and methods of the inventioninclude, at least: dexamethasone, dexamethasone alcohol, dexamethasonesodium phosphate, fluromethalone acetate, fluromethalone alcohol,lotoprendol etabonate, medrysone, prednisolone, prednisone, prednisoloneacetate, prednisolone sodium phosphate, rimexolone, hydrocortisone,hydrocortisone acetate, lodoxamide tromethamine, or a derivative orcombination thereof. It is understood, for any of the chemicals of thisdisclosure, that the chemicals may be in various modified forms such asacetate forms, and sodium phosphate forms, sodium salts, and the like.

Dexamethasone has the following chemical structure:

It is known that any of the reagents mentioned anywhere in thisdisclosure may be in chemically equivalent forms such as salts,hydrides, esters and other modifications of the basic chemical. Forexample, dexamethasone in any of the compositions and methods of theinvention may be replaced with any of its derivatives, including estersand salts thereof. Examples of such derivatives include, at least,Dexamethasone-17-acetate (CAS RN: 1177-87-3), Dexamethasone DisodiumPhosphate (CAS RN: 2392-39-4), Dexamethasone Valerate (CAS RN:14899-36-6), Dexamethasone-21-isonicotinate (CAS RN: 2265-64-7),Dexamethasone Palmitate (CAS RN: 33755-46-3), Dexamethasone Propionate(CAS RN: 55541-30-5), Dexamethasone Acefurate (CAS RN: 83880-70-0),Dexamethasone-21-galacto side (CAS RN: 92901-23-0), dexamethasone21-thiopivalate, dexamethasone 21-thiopentanoate, dexamethasone21-thiol-2-methyl-butanoate, dexamethasone 21-thiol-3-methyl-butanoate,dexamethasone 21-thiohexanoate, dexamethasone21-thiol-4-methyl-pentanoate, dexamethasone21-thiol-3,3-dimethyl-butanoate, dexamethasone21-thiol-2-ethyl-butanoate, dexamethasone 21-thiooctanoate,dexamethasone 21-thiol-2-ethyl-hexanoate, dexamethasone21-thiononanoate, dexamethasone 21-thiodecanoate, dexamethasone21-p-fluorothiobenzoate or a combination thereof. Dexamethasonederivatives are also described in U.S. Pat. No. 4,177,268.

Suitable topical anesthetics for the compositions and methods of theinvention include, at least, proparacaine, lidocaine, tetracaine or aderivative or combination thereof.

The compositions of the present invention can be administered assolutions, suspensions, emulsions (dispersions), gels, creams, orointments in a suitable ophthalmic vehicle.

In any of the compositions of this disclosure for topicaladministration, such as topical administration to the eye, the mixturesare preferably formulated as 0.01 to 2.0 percent by weight solutions inwater at a pH of 5.0 to 8.0 (figures relate to combined presence ofpovidone-iodine and dexamethasone). This pH range may be achieved by theaddition of buffers to the solution. We have found that, surprisingly,the formulation of the present invention is stable in bufferedsolutions. That is, there is no adverse interaction between the bufferand the iodine or other component that would cause the composition to beunstable. While the precise regimen is left to the discretion of theclinician, it is recommended that the resulting solution be topicallyapplied by placing one drop in each eye 1 to 24 times daily. Forexample, the solution may be applied 1, 2, 4, 6, 8, 12, 18 or 24 times aday.

Antimicrobial Preservative

As an optional ingredient, suitable antimicrobial preservatives may beadded to prevent multi-dose package contamination. Such agents mayinclude benzalkonium chloride, thimerosal, chlorobutanol, methylparaben, propyl paraben, phenylethyl alcohol, EDTA, sorbic acid, OnamerM, other agents known to those skilled in the art, or a combinationthereof. Typically such preservatives are employed at a level of from0.001% to 1.0% by weight.

Co-Solvents/Surfactants

The compositions of the invention may contain an optional co-solvent.The solubility of the components of the present compositions may beenhanced by a surfactant or other appropriate co-solvent in thecomposition. Such co-solvents/surfactants include polysorbate 20, 60,and 80, polyoxyethylene/polyoxypropylene surfactants (e.g. PluronicF-68, F-84 and P-103), cyclodextrin, tyloxapol, other agents known tothose skilled in the art, or a combination thereof. Typically suchco-solvents are employed at a level of from 0.01% to 2% by weight.

Viscosity Agents

The compositions of the invention may contain an optional viscosityagent—that is, an agent that can increase viscosity. Viscosity increasedabove that of simple aqueous solutions may be desirable to increaseocular absorption of the active compound, to decrease variability indispensing the formulation, to decrease physical separation ofcomponents of a suspension or emulsion of the formulation and/or tootherwise improve the ophthalmic formulation. Such viscosity builderagents include as examples polyvinyl alcohol, polyvinyl pyrrolidone,methyl cellulose, hydroxy propyl methylcellulose, hydroxyethylcellulose, carboxymethyl cellulose, hydroxy propyl cellulose, otheragents known to those skilled in the art, or a combination thereof. Suchagents are typically employed at a level of from 0.01% to 2% by weight.

The Formulation

The following two reactions must be considered for the chemistry ofPVP-I in aqueous solutions:

a. PVP-I₂⇄ PVP+I₂

b. PVP-HI₃⇄ PVP+H^(⊕)+I₃ ^(⊖)

The affinity of free iodine (I₂) for reaction with —OH, —SH and —NHfunctional groups is well described in the literature and forms thebasis for the anti-microbial activity of iodine-containing solutions(Rackur H. J. Hosp. Infect., 1985; 6: 13-23, and references therein).Dexamethasone (9-Fluoro-11β, 21-trihydroxy-16α-methylpregna-1,4-diene-3, 20-dione) contains three such moieties (—OH) at the 11, 17and 21 positions. A person in the field would conclude that thesehydroxyl groups would be prone to covalent substitution reactions by thefree iodine generated in the solution equilibrium reaction describedabove for PVP-I₂.

In deriving the present formulations, experiments of combinations ofvarious anti-inflammatories and PVP-I, or steroids and PVP-I, wereperformed. It was observed that most formulations were unsuccessfulbecause of the rapid reaction between PVP-I and the added reagent(anti-inflammatory or steroid). Some of these unsuccessful formulationsare described elsewhere in this disclosure. Particularly, the limitingfactor for lower concentrations of PVP-I solutions is stability andefficacy as a microbicidal.

It is thus the object of the present invention to discover novelformulation of combinations of PVP-I and an anti-inflammatory to solvethree problems of stability, efficacy and non-irritating to the eye. Wehave found, unexpectedly, that a 1% PVP-I solution is effective fortreatment of infection or prophylaxis of infections when combined withdexamethasone. The literature has previously indicated that while 1%PVP-I is desirable, the side effects of ocular administration precludedits use. The undesirable side effects include pain and irritation.

It was surprising to discover that the solution of PVP-I anddexamethasone remains stable for many months. Based on the stabilitydata disclosed, we conjecture that the compositions of the invention maybe stable for years—although experiments are still ongoing at thispoint. It is a further unexpected result that the reaction ofdexamathasone and PVP-I does not proceed to any appreciable extent atroom temperature, in light or dark, over time. Unexpectedly the reactionbetween the free iodine in solution and the hydroxyl groups present onthe dexamethasone molecule as compounded in our formulation does notproceed.

Due to the high propensity of oxidative potential of PVP-I, the resultedstable combination of PVP-I and dexamethasone is unexpected for theaverage worker/scientist/physician in this field. It was observed whenthe concentration of PVP-I is larger than 0.5%, a stable combinationformulation can be achieved. Surprisingly, it was found that 0.3% PVP-Icombination with dexamethasone was much less stable. This is once againunexpected because the lower concentrations of iodine are expected to beless reactive and hence, less destructive to either parts. After 8weeks, the available iodine in the combination (0.3% PVP-I initially)decreased by 20%. Though 0.1% diluted PVP-I has the strongestantimicrobial activity (Gottardi W. J. Hosp. Infect., 1985; 6(Suppl):1-11) our data showed we need at least 0.5% PVP-I in combination withdexamethasone to show the best antimicrobial activity. We have observedPVP-I reacted with Ketorolac (a non-steroidal anti-inflammatory) rapidlyand the Ketorolac was completely consumed and the available iodine inthe PVP-I complex was reduced significantly depending on the ratiobetween Ketorolac and PVP-I. The combination of PVP-I and dexamethasonesodium phosphate also proved to be less successful but also useful. Weobserved some dissociation of PVP-I complex to an unknown polymericcomplex in the UV spectra and the iodine reduction is around 5% after 12weeks. It was further observed that PVP-I reacts immediately withproparacaine and releases free iodine rapidly.

Surprisingly, the combination formulation has contributed to thestability of diluted PVP-I solution. The available iodine of a 0.625%povidone-iodine solution was 91% at 25° C. and 98% at 4° C. after 5weeks storage, respectively. (Iryo Yakugaku 2003, 29(1), 62-65). Ourdata showed that our formulation stabilized the diluted PVP-I solution.After 8 weeks at room temperature, the available iodine in solutionswith 0.5% and 1% PVP-I were over 99%.

The use of topical steroids alone is contraindicated in suspected viraland fungal infections of the human eye. Furthermore the use ofcombination anti-bacterial/steroid solutions is contraindicated in thesetting of suspected viral infection. There are no steroid-containingsolutions described that are safe for use in the human eye in thesetting of presumed viral or fungal infection. It is thereforeunexpected to the authors and others in the field that asteroid-containing solution would be of use in the treatment of an acuteviral or fungal ocular infection.

A potent anti-inflammatory steroid allows the temperance of thepotentially devastating ocular immune response in the setting of anactive infection. However, due to the antiseptic (antibacterial,antiviral, and antifungal, antiprotozoal) power of PVP-I, the compoundis useable in the setting of active infection without the risk ofworsening the infection. This unique property (poly-antimicrobicide andpotent anti-inflammatory) is a significant improvement over all otherocular antibiotics and anti-inflammatory.

Although a topical steroid is of tremendous benefit in the treatment ofocular inflammation, its use is fraught with risks. Topical steroidsapplied to the eye act by a variety of well described genomic andnon-genomic mechanisms to reduce the production of constituent proteinsof the inflammatory cascade, decrease vascular permeability, decreasethe production of pro-inflammatory cytokines, decrease the potency ofsoluble inflammatory factors, inhibit the production of acute phaseproteins, decrease leukocyte migration and increase the stability ofcell membranes. Through all of these mechanisms, topically appliedsteroids can reduce the local concentrations of activated products toxicto the eye including the gelatinase, collaginase andmatrixmetalloproteinase families of proteins. With this reduction inpotentially toxic substances comes the increased risk of prolongedinfection and potential infection. If the topical steroid is given incombination with an appropriate antimicrobial (i.e. and antibacterialfor bacterial infection, an antiviral for viral infection, an antifungalfor fungal infection) its risk can be reduced and/or eliminated. Theusual practicing ophthalmologist cannot reliably distinguish thecausative agent in most cases of acute external eye infection in a timeframe relevant to the prescription of treatment. Thus the beneficialeffects one may gain from the prompt use of topical steroids are delayedor eliminated entirely as the clinician either waits for culture resultsor more likely delays treatment indefinitely. The novel combination of apolymicrobicidal effective against bacteria, viruses and fungi and atopical steroid eliminates this risk and allows the immediate control ofinflammation and eradication of pathogen. In our view, this is the mostpreferred embodiment of the present invention.

We also noted that the other components in our preferred compositionappear to further stabilize the formulation. That is, the EDTA, sodiumchloride, tyloxapol, sodium sulfate and hydroxyethylcellulose appear tohave additional beneficial effects of further stabilizing thecomposition.

The invention has been described herein by reference to certainpreferred embodiments. However, as obvious variations thereon willbecome apparent to those skilled in the art, the invention is not to beconsidered as limited thereto. All patents, patent applications, andreferences cited anywhere is hereby incorporated by reference in theirentirety.

EXAMPLES

Throughout this section the letter “A” in a sample name refers toPovidone-Iodine complex (“PVP-I”), A00 refers to PVP-I at 0.0%, A03refers to PVP-I at 0.3%, A05 refers to PVP-I at 0.5%, A10 refers toPVP-I at 1.0%, A15 refers to PVP-I at 1.5%, A20 refers to PVP-I at 2.0%,A40 refers to PVP-I at 4.0% and so on.

Similarly, the letter “B, C, D, K, P” in a sample name refers todexamethasone, dexamethasone sodium phosphate, prednisolone sodiumphosphate, ketorolac (also called ketorlac) and proparacaine,respectively. B00 refers to dexamethasone at 0.0%, B01 refers todexamethasone at 0.1%, C01 refers to dexamethasone sodium phosphate at0.1%, D01 refers to prednisolone sodium phosphate at 0.1%, K01 refers toketorolac at 0.1%, and P008 refers to proparacaine at 0.08%, and so on.

Example 1 Production of Povidone-Iodine/Dexamethasone Suspensions

Amount (wt. %) Povidone-Iodine (PVP-I) 0.0 to 4.0 Dexamethasone,Micronized, USP 0.1  EDTA, USP 0.01 Sodium Chloride, USP 0.3  SodiumSulfate, USP 1.2  Tyloxapol, USP 0.05 Hydroxyethylcellulose 0.25Sulfuric Acid and/or Sodium hydroxide q.s. for pH adjustment to 5.7-6.0Sterile water, USP q.s. to 100

Experimental Procedures:

In a 1000 mL beaker was added 400 g sterile water, hydroxyethylcellulose(2.25 g, 0.25% w/w) was added under vigorous stirring with an overheadstirrer. Sodium chloride (2.70 g, 0.3% w/w) was slowly added whiledissolving, followed by addition of EDTA (0.09 g, 0.01% w/w) and sodiumsulfate (10.8 g, 1.2% w/w). After stirring for 10 minutes, tyloxapol(0.45 g, 0.05% w/w) dissolved in water was transferred into the abovesolution. The reaction mixture was stirred for 1 hour and q.s. to 540 gwith sterile water and was stirred for another 10 minutes to give “bulksolution 1.”

60 g each of the bulk solution 1 was transferred into two 125 mLbeakers, and povidone-iodine complex (0.5 g, 1.5 g) was added into therespective solution while stirring. The pH value was adjusted to therange of 5.7 to 6.0 by addition of sodium hydroxide or sulfuric acid andq.s. the suspensions to 100 g with sterile water to give control samplesA05B00 and A15B00, respectively.

The remaining 417 g of the bulk solution 1 was added dexamethasone (0.7g, 0.1% w/w) and homogenized for 5 minutes and then q.s. to 420 g togive bulk solution 2.

60 g each of the bulk solution 2 was transferred into seven 125 mLbeakers, and povidone-iodine complex (0.0 g, 0.3 g, 0.5 g, 1.0 g, 1.5 g,2.0 g, and 4.0 g) was added into the respective solution while stirring.The pH value was adjusted to the range from 5.7 to 6.0 by addition ofsodium hydroxide or sulfuric acid and q.s. the suspensions to 100 g withsterile water to give samples A00B01, A03B01, A05B01, A10B01, A15B01,A20B01 and A40B01, respectively. The LC-MS spectra of all samplesconfirmed the finding that there was no reaction between PVP-I anddexamethasone at all. The dexamethasone (MH⁺=392.9) peak has not beenaltered to other mass peaks.

Example 2 Production of Solutions of Povidone-Iodine/DexamethasoneSodium Phosphate; Povidone-Iodine/Prednisolone Sodium Phosphate; andPovidone-Iodine/Ketorolac

In a similar manner, solutions of A00C01, A03C01, A05C01, A10C01,A15C01, A00D01, A03D01, A05D01, A10D01, A15D01, A00K01, A05K01, A10K01,and A15K01 were produced.

The LC-MS spectra of A05C01, A10C01, and A15C01 confirmed thedexamethasone phosphoric acid (MH⁺=472.9) peak. The LC-MS spectra ofA05D01, A10D01, and A15D01 confirmed the prednisolone phosphoric acid(MH⁺=440.9) peak.

However, the LC-MS experiments of A05K01 and A10K01 confirmed thefinding of reaction between PVP-I and ketorolac tromethamine, ForA05K01, there was a small amount of ketorolac left in the sample(MH⁺=256.1), the major peak is: MH⁺=381.9. For A10K01 and A15K01, therewas no ketorolac left and has converted to a new compound (MH⁺=381.9)completely.

LC-MS experiments of A00B01P008 (control), A05B01P008 and A10B01P008confirmed the finding of reaction between PVP-I and proparacaine. Forthe control, two peaks: MH⁺=295.1 (proparacaine) and MH⁺=392.9(dexamethasone) were observed in the LC-MS spectrum. ComparingA05B01P008 with A10B01P008, the proparacaine peak (MH⁺=295.1) relativeto the dexamethasone peak (MH⁺=392.9) became much smaller, whichsuggests povidone iodine reacted with proparacaine.

Example 3 Production of Povidone-Iodine/Dexamethasone/ProparacaineSuspensions

Amount (wt. %) PVP-I 0.0 to 1.5 Dexamethasone, Micronized, USP 0.1 Proparacaine hydrochloride, USP 0.08% EDTA, USP 0.01 Sodium Chloride,USP 0.3  Sodium Sulfate, USP 1.2  Tyloxapol, USP 0.05Hydroxyethylcellulose 0.25 Sulfuric Acid and/or Sodium hydroxide q.s.for pH adjustment to 5.7-5.9 Sterile water, USP q.s. to 100

In a 400 mL beaker was added 100 g sterile water, hydroxyethylcellulose(0.75 g, 0.25% w/w) was added under vigorous stirring with an ARROWoverhead stirrer. Sodium chloride (0.9 g, 0.3% w/w) was slowly addedwhile dissolving, followed by addition of EDTA (0.03 g, 0.01% w/w),sodium sulfate (3.6 g, 1.2% w/w) and proparacaine hydrochloride salt(0.24 g, 0.08% w/w) sequentially. After stirring for 10 minutes,tyloxapol (0.15 g, 0.05% w/w) dissolved in water was transferred intothe above solution. The reaction mixture was stirred for 1 hour anddexamethasone (0.3 g, 0.1% w/w) was added and homogenized for 10 minutesand then q.s. to 180 g with sterile water to give the bulk solution 5.60 g each of the bulk solution 5 was transferred into four 125 mLbeakers, and povidone-iodine complex (0.0 g, 0.5 g, 1.0 g) was addedinto the respective solutions while stirring. The pH value was adjustedto around 5.8 by addition of sodium hydroxide or sulfuric acid and q.s.the solution to 100 g to afford samples A00B01P008, A05B01P008, andA10B01P008.

During the production of these samples, strong smell of iodine wasobserved. It was speculated that PVP-I reacted with proparacaine veryrapidly. The speculation was confirmed by LC-MS spectra. Thedexamethasone and proparacaine peaks in the combination samples withPVP-I became very small or even disappeared.

Stability of the Solutions

The amount of titratable iodine in the solutions was determined bytitration method after various week of sample storage at roomtemperature.

Titration Method: 5 mL of each sample was transferred into a 125 mLbeaker by pipette, and 1 mL of 1% (w/v) starch indicator solution wasadded. The solution was titrated with 0.0025N sodium thiosulfatesolution until the blue color disappeared completely. The volume ofsodium thiosulfate solution used was determined.Titratable Iodine (mg)=V (mL, volume used for titration)*12.69 (mg/mL)/2

The calculated titratable iodine (mg) is listed in Table 1.

TABLE 1 Stability Data Summary (Available Iodine) Iodine Iodine Iodine(mg) Iodine (mg) Iodine (mg) After (mg) after (mg) sample 0 wk 1 wkchange % 8 wks change % CLSA05B00 2.32 2.25 −3.02 CLSA15B00 7.31 7.17−1.92 CLSA03B01 1.36 1.27 −6.62 1.08 −20.59 CLSA05B01 2.27 2.32 2.2 2.25−0.88 CLSA10B01 4.28 4.28 0 4.25 −0.7 CLSA15B01 7.28 7.36 1.1 7.52 3.3CLSA20B01 9.87 9.9 0.3 9.71 −1.62 Iodine Iodine Iodine (mg) (mg) (mg)change % (After 4 wks) (After 12 wks) CLSA10C01 4.25 4 −5.9 CLSA15C016.79 6.54 −3.7 CLSA10D01 4.6 4.38 −4.8 CLSA15D01 6.44 6.41 −0.5 0 wkAfter 5 wks CLSA05K01 1.81 0 −100 CLSA10K01 4.54 1.87 −58.8 CLSA15K017.17 4.57 −36.3

The data of concentration of PVP-Iodine after weeks of storage at roomtemperature, either at dark or light, have suggested that stablecombination formulations have been achieved for PVP-iodine combinationswith dexamethasone, or dexamethasone sodium phosphate or prednisolonesodium phosphate. The 0.3% (wt. %) PVP-I combination with dexamethasoneis less stable than those of above 0.5% PVP-Iodine combinations withdexamethasone, which have less than 5% alteration of the availableiodine concentration after 8 weeks.

Data has also suggested PVP-I reacted with ketorolac tromethamine. At0.5% PVP-I in the sample after five weeks, there was no titratableiodine left. At 1.5% and 1.5% of PVP-I in the samples, the titratableiodine was depleted significantly at 58.8% and 36.3%, respectively.

Stability Test of Dexamethasone in the Sample using HPLC

The USP method was performed. The concentration of dexamethasone data istabulated in chart form below in Table 2:

TABLE 2 concentration concentration Concentration Samples (mg/mL)/3 wks(mg/mL)/7 wks change % CLS-A05B01 0.94 0.92 −2.13 CLS-A10B01 0.86 0.904.65 CLS-A15B01 0.93 0.86 −7.53

HPLC spectra have shown that there were no new peaks appearing comparedwith standard controls. The spectra suggested that there was no reactionbetween PVP-Iodine and dexamethasone at all.

Stability test of Dexamethasone Sodium Phosphate in the sample usingHPLC

The USP method was performed. The concentration data of dexamethasonesodium phosphate is tabulated in chart form below in Table 3. A05C01 (1day), A10001, A15C01 (3 days) in 40° C. oven.

TABLE 3 Initial Concentration Concentration Concentration Sample name(mg/mL) (mg/mL) Change % A05C01 1.273 1.244 −2.28 A10C01 0.948 1.07513.40 A15C01 1.355 1.148 −15.28

HPLC spectra have shown that there was a new peak appearing in thesamples of A10C01 and A15C01 compared with standard controls and A05C01.The concentrations of dexamethasone sodium phosphate were altered morethan 10% in the samples of A10C01 and A15C01.

In another experiment, we have found, surprisingly, that eye drops ofthe following formulation: 0.5 to 2% (w/w) polyvinylpyrrolidinone-iodinecomplex; 0.05 to 0.2% (w/w) steroid; 0.005% to 0.02% (w/w) EDTA; 0.0.1to 0.5% (w/w) sodium chloride; 0.02 to 0.1% (w/w) tyloxapol; 0.5% to 2%(w/w) sodium sulfate; and 0.1 to 0.5% (w/w) hydroxyethylcellulose;wherein said steroid is dexamethasone, prednisolone, prednisone, oracetate forms thereof, or sodium phosphate forms thereof were stable for1 month, 3 months and up to 6 months. Based on data gathered so far,such a solution appears to be capable of storage of up to at least 1year from the date for manufacturer. Stability is defined as a deviationin concentration of the major components (PVP-I and steroid) by lessthan 10% over a period of time. Thus, the PVP-I was not reduced to lessthan 90% over the period of 1 month, 3 months, and 6 months while thesolution is in storage and based on our data at 6 months, it appearsthat the solution would be stable for at least one year. Storageconditions was at room temperature, in clear bottles, in indoor lightingof 100 to 1000 lux of incandescent and/or fluorescent lighting. Thestability may be attributed to the unique combination of PVP-I anddexamethasone, prednisolone, prednisone (including acetate forms andsodium phosphate forms of these steroids). We have additionally foundthat the other reagents (EDTA, sodium chloride, tyloxapol, sodiumsulfate; and hydroxyethylcellulose) when present, further contributed tostability.

We have found, when comparing various formulations during development,that PVP-I confers a number of advantages in the formulation. Briefly,PVP-I formulations have the following improved properties compared to aniodine solution: (1) less irritating to the skin and eye, (2) washable,(3) increased stability, (4) increased stability in light, (5) lowsystemic toxicity, (6) less side effects. Also, based on currentknowledge, PVP-I is neutral with respect to scar tissue formation.

Example 4 Antimicrobial Assays

Solutions of PVP-iodine combinations with various anti-inflammatorysteroids were tested for antimicrobial activity against commonpathogenic bacteria, yeast, fungi and viruses. The broth inoculationmethod of Antimicrobial Assays (USP) was used to conduct the efficacytest of the treatment of various concentrations of the solutions ofPVP-iodine combinations against pure ocular isolates. It was found thatthe concentrations of PVP-iodine from 0.03% can dose-dependently producethe suppressing effects on microbial growth. The antimicrobial effectscan be further supported by completely eliminating all species testedwithin 72 hours of inoculating treatment with 0.03% solution. Theoptimal efficacy of antimicrobial effects can be achieved atconcentrations above 0.5%. Above the concentrations, the solution caneffectively kill and eliminate all species tested even under a conditionof immediate contact without further inoculation. For example, asolution of 1% PVP-iodine and 0.1% dexamethasone (wt %) was found tokill on contact Pseudomonas aeuroginosa, Proteus mirabilis, Serratiamaracescens, Staphylococcous aureus, Staphylococcus epidermidis,Streptococcus pneumoniae, Methicilin Resistant Staphylococcus Aureus,Klebsiella pneumoniae, Candida parapsilosis, Candida albicans andApergillus niger. The results clearly demonstrated the efficacy of thesolutions on eliminating microbial growth.

Example 5 Adenovirus Testing

Solutions of PVP-iodine combinations with dexamethasone were tested forantiviral activity against human adenovirus. A 0.5 mL aliquot of eachtest and control article was combined with 0.5 mL of virus stock in asterile tube. The tubes were then incubated at 37° C. for 30 minutes.A00B01 was used as the positive control. Hank's Balanced Salt Solution(HBSS) was used as the negative control. Immediately followingincubation the test and control articles were titrated for infectiousHAdV-4.

TABLE 4 Antiviral Activity Customer HAdV-4 Titer Sample Number (Log₁₀TCID₅₀/mL) A00B01 4.4 A10B01 ≦1.6 A15B01 ≦1.6 A20B01 ≦1.6 HBSS 4.0

Following a 30 minute incubation of the test articles with virus, A00B01had no effect on virus infectivity, but compounds A10B01, A15B01 andA20B01 resulted in complete inactivation of the virus.

Example 6 Human Eye Irritation Studies

All volunteers were examined before testing and found to have healthyeyes with no signs of disease. 1.0% PVP-Iodine solution alone was madeand tried in 15 healthy volunteers. Side effects of treatment wereimmediately reported. The side effects found included mild pain,discomfort, tearing, and redness. This is consistent because theliterature has previously indicated that 1% PVP-iodine is unsuitable foruse because of irritation that is unacceptable to the patient (e.g.,U.S. Pat. No. 5,126,127). From the reported side effects, it is clearthat a regiment of multiple applications to the volunteers would beintolerable.

The solution of A10B01, containing 1% PVP-I and 0.1% dexamethasone, wastested by seven healthy volunteers. Administration was by eye drop. Itwas surprisingly found that the solution was tolerable to the eye (doesnot burn) and was comfortable at a range of pH. Specifically, theformulation of pH 5.9 formulation is comfortable upon instillation intothe eye.

One person used the solution as an eye drop four times a day for aperiod of 3 days with no adverse side effects. Other pH values, such aspH 6 to 8, are obtainable either by adjusting the pH alone, with asuitable chemical such as sulfuric acid or sodium hydroxide, or by theaddition of a suitable buffer.

All volunteers were examined by physicians immediately after the trialperiod and in further follow-up examinations after a period of time.Further, volunteers were contacted by physicians at one month, twomonths and three months after trial and no adverse effects were reportedfor any of the volunteers.

We claim:
 1. A composition comprising a mixture of a) povidone-iodine ata concentration between 0.1% and 2.5% by weight, and b) a steroid at aconcentration of between 0.05 and 2% by weight, wherein the steroid isdexamethasone, and wherein, after a period of one month after mixing thesteroid and povidone-iodine to form the composition, the steroidconcentration is at least 90% by weight of the steroid startingconcentration, and wherein said composition is in the form of asuspension.
 2. The composition of claim 1, wherein said povidone-iodineis between 0.5% and 2% by weight.
 3. The composition of claim 1, whereinsaid composition further comprises an antimicrobial preservative.
 4. Thecomposition of claim 3, wherein said antimicrobial preservative isselected from the group consisting of benzalkonium chloride, thimerosal,chlorobutanol, methyl paraben, propylparaben, phenyl ethyl alcohol,ethylenediaminetetraacetic acid, sorbic acid, polyquarternium 1, and acombination thereof.
 5. The composition of claim 4, wherein saidco-solvent/surfactant is ethylenediaminetetraacetic acid.
 6. Thecomposition of claim 5, wherein said antimicrobial preservative is at aconcentration of about 0.001% to 1.0% by weight in said composition. 7.The composition of claim 1, wherein said composition further comprises aco-solvent/surfactant.
 8. The composition of claim 7, wherein saidco-solvent/surfactant is selected from the group consisting ofpolysorbate 20, polysorbate 60, polysorbate 80, Pluronic F-68, PluronicF-84, Pluronic P-103, cyclodextrin, tyloxapol, and a combinationthereof.
 9. The composition of claim 8, wherein saidco-solvent/surfactant is tyloxapol.
 10. The composition of claim 9,wherein said co-solvent/surfactant is at a concentration of about 0.01%to 2% by weight in said composition.
 11. The composition of claim 1,wherein said composition further comprises a viscosity increasing agent.12. The composition of claim 11, wherein said viscosity increasing agentis selected from the group consisting of polyvinyl alcohol,polyvinylpyrrolidone, methyl cellulose, hydroxypropyl methylcellulose,hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropylcellulose, and a combination thereof.
 13. The composition of claim 12,wherein said viscosity increasing agent is hydroxyethyl cellulose. 14.The composition of claim 13, wherein said viscosity increasing agent isat a concentration of about 0.01% to 2% by weight in said composition.15. The composition of claim 1, comprising: 0.5 to 2% (w/w)povidone-iodine; 0.05 to 2% (w/w) steroid; 0.005% to 0.02% (w/w)ethylenediaminetetraacetic acid; 0.01 to 0.5% (w/w) sodium chloride;0.02 to 0.1% (w/w) tyloxapol; 0.5% to 2% (w/w) sodium sulfate; 0.01 to0.5% (w/w) sodium chloride; and 0.1 to 0.5% (w/w) hydroxyethylcellulose.16. The composition of claim 1, comprising: 0.5 to 2% (w/w)povidone-iodine; 0.05 to 2% (w/w) steroid; 0.01% (w/w)ethylenediaminetetraacetic acid disodium salt; 0.01 to 0.5% (w/w) sodiumchloride; 0.05% (w/w) tyloxapol; 1.2% (w/w) sodium sulfate; 0.01 to 0.5%(w/w) sodium chloride; and 0.25% (w/w) hydroxyethylcellulose.
 17. Thecomposition of claim 1, comprising: 0.5 to 2% (w/w) povidone-iodine;0.1% (w/w) steroid; 0.01% (w/w) ethylenediaminetetraacetic acid disodiumsalt; 0.01 to 0.5% (w/w) sodium chloride; 0.05% (w/w) tyloxapol; 1.2%(w/w) sodium sulfate; 0.01 to 0.5% (w/w) sodium chloride; and 0.25%(w/w) hydroxyethylcellulose.
 18. A composition comprising a mixture ofa) povidone-iodine at a concentration between 0.1% and 2.5% by weight,and b) a steroid at a concentration of between 0.05 and 2% by weight,wherein the steroid is dexamethasone, and wherein, after a period of onemonth after mixing the steroid and povidone-iodine to form thecomposition, the povidone-iodine concentration is at least 90% by weightof the povidone-iodine starting concentration, and wherein saidcomposition is in the form of a suspension.
 19. The composition of claim18, wherein said povidone-iodine is between 0.5% and 2% by weight. 20.The composition of claim 18, wherein said composition further comprisesan antimicrobial preservative.
 21. The composition of claim 20, whereinsaid antimicrobial preservative is selected from the group consisting ofbenzalkonium chloride, thimerosal, chlorobutanol, methyl paraben,propylparaben, phenyl ethyl alcohol, ethylenediaminetetraacetic acid,sorbic acid, polyquarternium 1, and a combination thereof.
 22. Thecomposition of claim 21, wherein said antimicrobial preservative is at aconcentration of about 0.001% to 1.0% by weight in said composition. 23.The composition of claim 22, wherein said composition further comprisesa co-solvent/surfactant.
 24. The composition of claim 23, wherein saidco-solvent/surfactant is selected from the group consisting ofpolysorbate 20, polysorbate 60, polysorbate 80, Pluronic F-68, PluronicF-84, Pluronic P-103, cyclodextrin, tyloxapol, and a combinationthereof.
 25. The composition of claim 24, wherein saidco-solvent/surfactant is tyloxapol.
 26. The composition of claim 25,wherein said co-solvent/surfactant is at a concentration of about 0.01%to 2% by weight in said composition.
 27. The composition of claim 17,wherein said composition further comprises a viscosity increasing agent.28. The composition of claim 27, wherein said viscosity increasing agentis selected from the group consisting of polyvinyl alcohol,polyvinylpyrrolidone, methyl cellulose, hydroxypropyl methylcellulose,hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropylcellulose, and a combination thereof.
 29. The composition of claim 28,wherein said viscosity increasing agent is hydroxyethyl cellulose. 30.The composition of claim 29, wherein said viscosity increasing agent isat a concentration of about 0.01% to 2% by weight in said composition.31. The composition of claim 17, comprising: 0.5 to 2% (w/w)povidone-iodine; 0.05 to 2% (w/w) steroid; 0.005% to 0.02% (w/w)ethylenediaminetetraacetic acid; 0.01 to 0.5% (w/w) sodium chloride;0.02 to 0.1% (w/w) tyloxapol; 0.5% to 2% (w/w) sodium sulfate; 0.01 to0.5% (w/w) sodium chloride; and 0.1 to 0.5% (w/w) hydroxyethylcellulose.32. The composition of claim 17, comprising: 0.5 to 2% (w/w)povidone-iodine; 0.05 to 2% (w/w) steroid; 0.01% (w/w)ethylenediaminetetraacetic acid disodium salt; 0.01 to 0.5% (w/w) sodiumchloride; 0.05% (w/w) tyloxapol; 1.2% (w/w) sodium sulfate; 0.01 to 0.5%(w/w) sodium chloride; and 0.25% (w/w) hydroxyethylcellulose.
 33. Thecomposition of claim 17, comprising: 0.5 to 2% (w/w) povidone-iodine;0.1% (w/w) steroid; 0.01% (w/w) ethylenediaminetetraacetic acid disodiumsalt; 0.01 to 0.5% (w/w) sodium chloride; 0.05% (w/w) tyloxapol; 1.2%(w/w) sodium sulfate; 0.01 to 0.5% (w/w) sodium chloride; and 0.25%(w/w) hydroxyethylcellulose.